EPA Radon Zone Context

The EPA recommends fixing a home if a measured radon test result is 4 pCi/L or more. An EPA county zone is not a home test and cannot be compared with that action level.

Short-term test kits ($12-30 at hardware stores) measure radon over 2-7 days and give a quick screening result. Long-term test kits (90+ days) provide a more accurate annual average. Digital continuous radon monitors ($150-200) give ongoing readings. Place the test in the lowest livable area of your home with windows and doors closed.

A standard sub-slab depressurization system costs $800-2,500 for most homes. This involves installing a pipe through the foundation slab and a fan that draws radon gas from beneath the home and vents it above the roofline. The system runs continuously and typically reduces radon levels by 80-99%. Annual electricity cost is about $50-75.

Yes. Radon comes from natural uranium decay in soil and rock beneath any building regardless of age. New construction may have radon-resistant features (sealed foundation, passive pipe), but these do not guarantee low levels. The EPA recommends testing every home, including new construction, before and after occupancy.

Radon seeps into buildings through cracks in foundation slabs, gaps around pipes and wires, construction joints, crawl spaces, and well water. The pressure difference between indoor air and soil drives radon upward. Basements and first floors typically have the highest concentrations. Granite countertops are not a significant radon source despite common claims.